Unity 2d UI 实时跟随场景3d物体

2d UI 实时跟随场景3d物体位置，显示 3d 物体头顶信息，看起来像是场景中的3dUI，实质是2d UI

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using DG.Tweening;
using UnityEngine.UI;
/// <summary>
/// 2d UI 实时跟随场景3d物体位置，显示 3d 物体头顶信息，看起来像是场景中的3dUI，实质是2d UI
/// </summary>
public class UIFollow3DGameObject : MonoBehaviour
{public Vector3 targetPos;private Camera mainCamera;private CanvasGroup canvas;bool _isInCamera = true; //是否在摄像机视野范围内void Awake(){mainCamera = Camera.main;canvas = GetComponent<CanvasGroup>();if (canvas == null){canvas = gameObject.AddComponent<CanvasGroup>();}_isInCamera = IsInCamera(mainCamera,targetPos);}/// <summary>/// 判断是否在摄像机视野范围内/// </summary>/// <returns></returns>bool IsInCamera(Camera camera,Vector3 pos){//转化为视角坐标Vector3 viewPos = camera.WorldToViewportPoint(pos);// z<0代表在相机背后if (viewPos.z < 0) return false;//太远了！看不到了！if (viewPos.z > camera.farClipPlane)return false;// x,y取值在 0~1之外时代表在视角范围外；if (viewPos.x < 0 || viewPos.y < 0 || viewPos.x > 1 || viewPos.y > 1) return false;return true;}void LateUpdate(){if (IsInCamera(mainCamera, targetPos) != _isInCamera){Debug.Log("改变是否在视野范围内");_isInCamera = IsInCamera(mainCamera, targetPos);MaskableGraphic[] childs = GetComponentsInChildren<MaskableGraphic>();foreach (var item in childs){item.enabled = _isInCamera;}if (_isInCamera == false) return;}if (targetPos != null && mainCamera != null){ResetPos();if (Time.frameCount % 5 == 0){ResetAlpha();}}}void ResetPos(){transform.position = mainCamera.WorldToScreenPoint(targetPos);}void ResetAlpha(){if (transform.position.z > 0f && canvas.alpha < 0.1f){canvas.alpha = 1f;}else if (transform.position.z < 0f && canvas.alpha > 0.9f){canvas.alpha = 0f;}}}